# ---
# title: 872. Leaf-Similar Trees
# id: problem872
# author: Tian Jun
# date: 2020-11-14
# difficulty: Easy
# categories: Tree, Depth-first Search
# link: <https://leetcode.com/problems/leaf-similar-trees/description/>
# hidden: true
# ---
# 
# Consider all the leaves of a binary tree, from left to right order, the values
# of those leaves form a **leaf value sequence** _._
# 
# ![](https://s3-lc-upload.s3.amazonaws.com/uploads/2018/07/16/tree.png)
# 
# For example, in the given tree above, the leaf value sequence is `(6, 7, 4, 9,
# 8)`.
# 
# Two binary trees are considered _leaf-similar_  if their leaf value sequence
# is the same.
# 
# Return `true` if and only if the two given trees with head nodes `root1` and
# `root2` are leaf-similar.
# 
# 
# 
# **Example 1:**
# 
# ![](https://assets.leetcode.com/uploads/2020/09/03/leaf-similar-1.jpg)
# 
#     
#     
#     Input: root1 = [3,5,1,6,2,9,8,null,null,7,4], root2 = [3,5,1,6,7,4,2,null,null,null,null,null,null,9,8]
#     Output: true
#     
# 
# **Example 2:**
# 
#     
#     
#     Input: root1 = [1], root2 = [1]
#     Output: true
#     
# 
# **Example 3:**
# 
#     
#     
#     Input: root1 = [1], root2 = [2]
#     Output: false
#     
# 
# **Example 4:**
# 
#     
#     
#     Input: root1 = [1,2], root2 = [2,2]
#     Output: true
#     
# 
# **Example 5:**
# 
# ![](https://assets.leetcode.com/uploads/2020/09/03/leaf-similar-2.jpg)
# 
#     
#     
#     Input: root1 = [1,2,3], root2 = [1,3,2]
#     Output: false
#     
# 
# 
# 
# **Constraints:**
# 
#   * The number of nodes in each tree will be in the range `[1, 200]`.
#   * Both of the given trees will have values in the range `[0, 200]`.
# 
# 
## @lc code=start
using LeetCode

function leaf_similar(root1::TreeNode{V}, root2::TreeNode{V})::Bool where {V}
    leaves1 = V[]
    leaves2 = V[]
    find_leaves!(root1, leaves1)
    find_leaves!(root2, leaves2)
    return leaves1 == leaves2
end

function find_leaves!(t::TreeNode, leaves)
    if isnothing(t.left) && isnothing(t.right)
        push!(leaves, t.val)
    else
        find_leaves!(t.left, leaves)
        find_leaves!(t.right, leaves)
    end
end

find_leaves!(::Nothing, leaves) = nothing
## @lc code=end
